sinew - a little lateral thinking?

[stuckinthemud]

OK, so, if I have a bow that already has all the reflex I want, could I draw it straight, then add the sinew, then let it relax into its original reflex to cure?  Would this have the same effect as adding sinew to a straight bow then pulling it into reflex to cure?

[PatM]

Not quite.

[stuckinthemud]

Fair enough, why? If I take a suitably long time to relax  the bow back into its reflex, how is that different from winding reflex into a straight bow as it cures?

[jeffp51]

It seems to me you want the wood and the sinew in tension.  With your scenario you would be relaxing the tension in the wood, although the sinew should be at the same level of tension.  That is just how I imagine it in my mind.  Best thing to do would be try it and see what happens.

[bradsmith2010]

i would just add the sinew,, depending on the wood,, it might add some reflex ,,, when you tiller it ,,,, it will pull some of that out, and you will end up about where the stave started,,

[maitus]

I think You are on the right way. If You sinew back already reflexed bow You will have too much reflex for a wooden bow. No matter that part of reflex pulls out. The out pulled sinew is already under the tension too early . If Your bow is not made from osage, yew or juniper, I wouldn't sinew back this bow under the existing reflex. I would do it exactly like You intended but i would live some reflex, I wouldn't make the bow completely straight ....

I forgot to mention lilac


 

[bradsmith2010]

alot depends on how much sinew you put as well,,
a thin layer probably not gonna induce much reflex,,
the thicker the layer the more likely to induce reflex,, and its hard to measure that,,
I stick with my original suggestion,,
put a medium layer of sinew and go with it as is,, pulling the natural reflex out of the bow to put sinew on,, seems counter productive,, it would work,, but you are likely just reducing the performance of the bow,,

[maitus]

pulling the natural reflex out of the bow to put sinew on,, seems counter productive

Why the bow should lose natural reflex if to straighten it for a short time for sinewing. Its like stringing the bow. As the sinew drys he will set free the clamps and the natural reflex will return. He won't heat or steam the bow. I think.... .

[bradsmith2010]

ok I guess I dont understand,,

[maitus]

ok I guess I dont understand,,

That's because of my English is bad .

[PatM]

It's just much more sensible to reflex the bow a bit and then add the sinew and then add a touch more and wind it tighter as it cures.

 No reason to complicate things.

[maitus]

How much reflex You have naturally?

[bownarra]

It's just much more sensible to reflex the bow a bit and then add the sinew and then add a touch more and wind it tighter as it cures.

 No reason to complicate things.

It already is reflexed a bit.
I guess the question is more like how much reflex can a wooden bow have before the belly starts to break down and you get no net advantage.
Answer a couple inches max. Anymore (other than with a very short drawlength) and you will simply get squashed belly cells leading to much lower compression resistance. Once this has gone you've got a sluggish bow that you put lots of work into.
As Maitius says yew/juniper/osage and perhaps a few others can handle the reflex. but most woods can't. Remember that 1% extension or compression You simply can't get around that fact.

[stuckinthemud]

The bow is naturally reflexed and is already tricky to string.  I'm not going to heat treat or steam unless I have to straighten it before I sinew it. I really don't want to end up with more reflex but I am going to put on a pretty thick layer of sinew - I've stripped most of the sapwood off a short and challenging yew stave I would have otherwise burned so its a great practice piece as there's no loss if everything goes pear-shaped, but its going to be interesting to see how a sinew backed yew heartwood bow performs, if it holds together.....

[bjrogg]

I’m not sure I understand. If  you “temporarily “ Straighten bow to apply sinew like stringing a bow. It seems to me the sinew would do nothing but add weight after you let  stave return to its natural reflex state. The sinew would all be loose and not in tension. I’m not sure I’m understanding question though.
I’ve never done a sinew backed bow either but many I’ve seen done were intensionally slightly reverse stung to add a bit off reflex and tension for the sinew. As the sinew dried it pulled a bit more reflex and tension on the sinew. I’m thinking this would allow better performance from your sinew.
Bjrogg